Various imidazoline derivatives particularly those having amphoteric properties have been suggested and used in surfactant compositions. Thus, in U.S. Pat. No. 3,408,361 of Hans S. Mannheimer dated October 29, 1968, certain hydroxyethyl imidazolines are described. Other art in United States Patent is U.S. Pat. Nos. 2,155,877 to Waldmann (1939) and 2,267,965 to Wilson (1941) and U.S. Pat. No. 2,520,102 to Tryon (1950). These imidazoline products are obtained by reacting a diamine for example, one of the formula NH.sub.2 C.sub.2 H.sub.4 NHR.sub.a --OH and a fatty acid of generic formula R--COOH wherein R is 5 to 25 carbon atoms and is alkyl or alkenyl, R.sub.a is R.sub.1 (OR.sub.1).sub.n in which R.sub.1 is an alkylene of 2 to 4 carbon atoms and n is 0 to 4. The amines used in preparing the condensates have primary amino groups and a second primary or a secondary amino group in 1:2 position to each other. In the aforesaid United States Patent the diamine and fatty acid are reacted to remove water of reaction. When only one mole of water is removed an open-chain product is obtained, considered to be for example, in the instance where n is 0 of the formula: ##STR1## which can be described as an amide. If more than one mole of water is removed the imidazoline ring structure is considered to be formed giving for example, in the instance where n is 0 product of formula: ##STR2## For convenience the imidazoline ring structure in this specification if formalized: the correct formula is: ##STR3## The imidazoline can be converted to the open-chain structure by hydrolysis and in the art these open-chain products whether originally or by hydrolysis are regarded from many aspects as having the equivalent properties to the imidazolines although not demonstrating the closed ring structure. Moreover, the initial condensation product generally contains a mixture of open-chain and ring closed (imidazoline) products.
The preparation of an imidazoline substituted in the 2-position by a long chain aliphatic hydrocarbon radical is well described in the literature and is readily carried out by reaction described above between a carboxylic acid and a polyamine containing at least one primary amino group and at least one secondary amino group. Since to obtain the product of the present invention it is necessary to obtain at some time the hydroxy group on a 1-aliphatic hydrocarbon substituent usually the hydroxy ethyl type amine is desirable but a hydroxy group can be substituted on to the appropriate 1-alkylene side-chain by those methods normal in the art.
A nitrogen on the ring has been further reacted with an alkylating agent, for example, sodium chloroacetate, (U.S. Pat. No. 2,528,378 of Mannheimer 1950) to provide structures considered as having the formula: ##STR4## wherein R and R.sub.1 are as defined above and R.sub.3 is an alkylene group of 1 to 3 carbon atoms, for example, methylene.
When in hydrolyzed or open chain form such structures could be regarded as having the structure: ##STR5##
Correspondingly, the imidazolines may be reacted with a monocarboxylic unsaturated acid or ester (United Kingdom Pat. No. 1,078,101 of Arndt, 1967 and U.S. Pat. No. 3,555,041 of Katz) to provide structures considered as having the formula: ##STR6## wherein R and R.sub.1 are as defined above and R.sub.2 is alkylene of 2 to 4 carbon atoms.
When in hydrolyzed or open chain form such structures could be regarded as having the structure: ##STR7##
As mentioned, in U.S. Pat. No. 2,528,378 there is described the preparation of a condensate of a diamine with a fatty acid which is then further reacted with a monohalo monocarboxylic acid particularly a metal salt thereof.
Such products have been found to demonstrate various surfactant or detergent properties and to be useful in products requiring good foaming properties and particularly those requiring fine bubble structure with good stability, for example, shampoo compositions. Nevertheless, despite the improvements obtained there is still a need for improvement in foam structure and stability of compositions particularly shampoo compositions. The present invention has as its objects imidazolines and the related open-chain structures which products can also be described as modified condensation products of diamines and fatty acids, having improved properties for use in detergent or surfactant compositions, for example, shampoos.